• Asian Journal of Turfgrass Science
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• v.18 no.3
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• pp.149-163
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• 2004

Physical and chemical properties of root zone mixes and methods of green construction are important considerations for improving turf grass quality for putting greens. This study compared Penncross creeping bentgrass (Agrostis palustris Huds.) performance as affected by three root zone construction systems with three amendments (sand, peat, and zeolite). The objective of this study was to determine if an amended California construction system would improve green performance during establishment (1998-1999) and maturation (2000-2001). Three treatments were tested: California ($100\%$ sand), USGA($90\%$ sand and $10\%$ peat, v/v), and California-Z ($85\%$ sand and $15\%$ zeolite, v/v). Treatments were arranged in a randomized complete block with four replicates. Physical and chemical properties of the root zone and bentgrass performance were compared for the treatments. The California-Z treatment had the highest saturated hydraulic conductivity, field infiltration rate and the lowest bulk density. It also had the highest cation exchange capacity and plant available nutrient concentrations among the three treatments. The California-Z treatment produced bentgrass quality and color during green establishment and maturation that were equal to or higher than the California treatment, and consistently higher than the USGA treatment. The addition of an inorganic amendment to the California system improved physical and chemical properties of the root zone and improved quality and color of bentgrass during green establishment. During green maturation, creeping bentgrass in the California-Z treatment was equal (6 of 15 sampling dates) or $20\%$ higher (9 of 15 dates) in quality compared to the California system.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.110-125
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• 2011

A number of the Bronze Age dwelling sites have been found and excavated in the Yoodoocheon, Onyangcheon and Baekseokdong basins. Two basins are located near Asan and Onyan in the Chungnam Province of South Korea. Baekseokdong is located in Cheonan, Chungnam. 207 dwelling sites are concentrated around the area of $1.3km^2$ in the Baekseokdong. 177 dwelling sites are sparse and distributed over the area of $1.3km^2$ in the Yongdoocheon and Onyangcheon basins. Most of the Bronze Age dwelling sites in those areas located on the hill. The hills have similar geomorphological environments except for slight differences in geological faces. This study analyzes geomorphological environments of the high-density residential zone of the Bronze Age in the Yoodoocheon and the Onyangcheon basins, and then compares them with the results in Baekseokdong. Study results show that high-density residential zone consists mainly of specific micro-landforms such as the Crest slope, the Crest flat and the Upper side slope, and southeast-facing aspect. A lot of Gentle slope lands were distributed in terms of terrain slope but it is far from specific geomorphological environments. This is not weighted in specific value. Our results show that the geomorphological characteristic derived from this study is major considerations to develop dwelling sites in the Bronze Age. This can be useful to discover the possible dwelling sites over other Chungnam hill regions.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.394-406
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• 2019

Difficult ground conditions (e.g., fault zone and mixed grounds) are highly probable to appear in subsea and urban tunnels because of the shallow working depth and alluvial characteristics. TBM usually experienced decrease of penetration rate and increase of downtime when it meets these difficult ground conditions. The problems are usually caused by the adverse geological conditions, and it is preferable to determine the optimal operational parameters of TBM based on the previous operational data obtained while excavating a preceding tunnel. This study carried out for efficient TBM excavation in fault zone and mixed grounds. TBM excavation data from the tunnel site in Singapore and the characteristics of the TBM excavation data was analyzed. The key operational parameters (i.e., thrust, torque, and RPM), penetration rate, and downtime were highly influenced by the presence of fault zones and mixed grounds, and the features was discussed. It is expected that the results and main discussions will be useful information for future tunneling projects in similar geological conditions.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.25-25
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• 2019

1953년 7월 27일 정전협정 이후 한반도를 가로지르는 DMZ (Demilitarized zone: 비무장지대)가 설정되었다. DMZ에 출입은 군사정전위원회의 허가가 있어야 가능하기에 군사시설 및 군작전지역을 포함하여 DMZ 및 민간인통제선 이북은 민간인 접근의 제한으로, 단절된 공간으로 변모하였다. DMZ는 우리나라의 대표적인 동고서저의 지형 및 다양한 생태환경을 두루 갖추고 있어 중요한 생태적 요충지로 평가받고 있다. 산림지역은 민간인통제지역까지 합치면 40여개의 산지가 분포하고 있으며, 하천은 크게 15개의 크고 작은 하천이 위치하고 있다. 남방한계선 수계를 따라 일부지역들은 하천 배후습지, 묵논습지 등 습원형태로도 많이 발견되고 있다. 이런 습원지역들은 대부분 미확인 지뢰지대로 접근이 제한적인 만큼 지난 세월의 흔적들을 고스란히 담고 있다. 1965년 한국자연보존연구회는 30여명의 국내학자를 동원하여 서울에서 가까운 DMZ 인접지역에 대한 예비적인 학술조사를 실시하였으며, 이를 계기로 1966년 10월부터 1968년 9월까지 2년간에 걸쳐 한국자연보존위원회 34명의 국내학자와 미국 스미소니언연구소(Smithsonian Institution) H. K. Buechner 박사를 대표로 5명의 국외학자가 공동으로 종합적인 학술조사를 수행하였다. 이는 DMZ 연구의 시작을 알렸으며, 이후 남북관계나 시대여건에 맞추어 간헐적으로 다양한 조사 및 연구들이 이어져오고 있다. 2015년부터 2018년까지 DMZ 철책주변 현장조사를 통해 확인된 식물현황은 964분류군이다. 군시설로 인해 식물서식환경이 제한적인 상황이지만 척박한 환경에 적응하고 있는 식물은 다양하다. DMZ와 맞닿아 있는 7개 지역에 대한 식물현황은 철원 638분류군, 연천 631분류군, 양구 525분류군 순으로 나타났다. 대부분 중동부 지역에 높은 식물종수가 나타났으며, 서부와 동부의 식물들이 고르게 나타나는 결과로 보인다. 큰잎쓴풀, 봉래꼬리풀 등 희귀식물도 있는 반면, 잠재적으로 생태계에 영향을 줄 수 있는 침입외래식물도 다수 포함되어 있어서, 지속적인 모니터링 및 관리가 필요하다. 그 중에서도 양구지역에 새롭게 발견된 Macleaya cordata (Willd.) R.Br.(양귀비과)는 독성이 포함된 식물이며, 인제에서 2014년에 발견된 미역취아재비는 DMZ일원에 제한적으로 분포하는 종이였으나 현재 연천에서 발견되는 등 확산에 대한 관리방안이 필요하다.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.331-341
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• 2016

A small irrigation pond for a rice paddy field is a very important refuge for aquatic insects and plants. To reveal environmental factors determining species composition of aquatic insect and plant communities, we analyzed water chemistry and connection between pond and surrounding in five types of irrigation ponds based on water source and connection in CCZ of South Korea: stagnation, exchange-stagnation, spring, stagnation-spring, and exchange-spring types. The stagnation type had the most stable water chemistry among the 16 irrigation ponds studied, and the spring type had the most variable water chemistry. Anion content was highest in the stagnation type, and cation content was highest in the exchange-stagnation type. 228 taxa including 63 wetland plants and 95 aquatic insect taxa were recorded. Six rare plant species and four rare aquatic insect species were identified. The stagnation-spring type had the highest species richness. There was no correlation between size and species richness. Multivariate analyses showed distinctive species assemblages among the irrigation pond types. This would indicate that water chemical change at annual cycle and connection influenced on the species assemblages in irrigation pond. In additional, irrigation pond contributes to regional biodiversity in agricultural areas, as irrigation pond provides heterogeneous communities for the freshwater ecosystem.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.273-280
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• 2001

We investigated the flora and vegetation structure of exotic plants along stream geomorphology and disturbance factors in the riparian zone of Seunggi stream, Incheon. Total 53 exotic plant species were found in the riparian corridors of Seunggi stream. The percentage of exotics ranged from 25% to 33% of total species richness, and its mean value was 24% in the whole riparian area. The percentage of exotics reflected the vulnerability of riparian zones to plant invasions by disturbances, and it could be used as an indicator of riparian system dysfunction. The distinct distribution patterns of exotic plants did not found in the lateral topographic features of the stream. Invasion and proliferation of the exotic plants were somewhat remarkable at terraces and bank slopes of the stream. Among various disturbance factors, plowing and trampling were important on the invasion of exotic plant species of Seunggi stream.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.737-744
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• 2012

Recently VoIP has provided voice(both wired and wireless from IP-based) as well as the transmission of multimedia information. VoIP used All-IP type, Gateway type, mVoIP etc. Wired and wireless VoIP has security vulnerabilities that VoIP call control signals, illegal eavesdropping, service misuse attacks, denial of service attack, as well as wireless vulnerabilities etc. from WiFi Zone. Therefore, the analysis of security vulnerabilities in wired and wireless VoIP and hacking incidents on security measures for research and study is needed. In this paper, VoIP (All-IP type, and for Gateway type) for system and network scanning, and, IP Phone to get the information and analysis of the vulnerability. All-IP type and Gateway type discovered about the vulnerability of VoIP hacking attacks (Denial of Service attacks, VoIP spam attacks) is carried out. And that is a real VoIP system installed and operated in the field of security measures through research and analysis is proposed.

• Economic and Environmental Geology
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• v.32 no.3
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• pp.217-225
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• 1999

Nine cauldrons have been recognized in the PVD (Pusan- Taegu Volcano-tectonic Depression) zone covering an area of nearly 7,000 $km^{2}$. They form characteristic landscape features with various mountains in the southeastern Kyongsang basin. Economically important ore deposits are also developed either in the ring fracture zone or the central pluton within the resurgent cauldrons or in the marginal area of the PVD, suggesting that these cauldrons played a major role in the distribution of ore deposits in the southeastern Kyongsang basin. Furthermore, the cauldron subsidences were more frequent with the more felsic volcano-plutonic complex, possibly indicating that the amounts of water and volatile components also acted as a controlling factor to cause the caldera subsidence and to concentrate the ore-forming elements in economic concentrations. The review of the relationship and variations of ore mineralization and cauldron subsidence is rather sketchy, but it provides a skeleton to carry out more detailed and quantitative studies related to temporal and spatial relationships between each cauldron subsidence accompanying its own ore mineralization. In the southeastern Kyongsang basin, additional calderas and associated ore deposits undoubtedly can be discovered through future detailed studies. The concept that cauldron subsidence are an important control for the formation of ore deposits will appear to be vindicated.

• Korean Journal of Microbiology
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• v.7 no.3
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• pp.107-114
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• 1969

Relationship of soil properties and seasonal variation on microbilogical population to-continuous culture and first-time culture of ginseng was investigated by bimonthly from May 1976 to January 1977. pH and P contents of 2 years continuous culture of soil were higher than other culture plot of soil, and contraty to the above, 2 years first-time culture of ginseng soil was conplot of soil, and contraty to the above, 2 years first-time culture of ginseng soil was contained more potassium contents than other culture plot of soil. In microbiological fluctuation with seasonr in various soil conditions, the population, trends of Fusarium spp., Erwiniaspp., and flourescent Psedudomonas spp. were increased in May and July in general, but decreased in the other month. It was observed that in all type of soil, Fusarium spp. was distributed in abundance in and on rihizosphere, and decreased the propagules numbers as soil depth increase. The numbers of Erwinia spp. and fluorescent Pseudo-monas spp. were distributed greater in numbers on the surface zone of soil depth decreasing the numbers along the soil layer increase, and also in 2years continuous culture of soil especially, a great numbers of Erwinia spp. and fluorescent Pseudomonas were evenly distributed in surface zone and rhizosphere. Ginseng disease with a high incidence of bacterial disease in continuous culture of 2 and 4 years was seemed to be associated with soil bacteria that was high in numbers of Erwinia spp. and fluorescent Pseudomonas spp. in May and July.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.55-58
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• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.